Thanks. Finally figured it out, had no idea it was just random. That's a pretty clumsy way to handle matters if at first you fail to get the ring.
Well, I got past that and plowed through the three tasks. Now I've seen another sex card, of a peasant girl, and am trying to figure out which peasant girl it is and how to lay her ... already did Vesna!

I didn't get if you're just looking or if you want to just know where she is and how to get her card.
If you just want to know it's here

Over all stages of this game will you find random proposals/missions/ideas/sex-cards from the nameless population on the streets. If you don't greet everyone in the vicinity at some point, you *will* miss something. That's how it goes...